The spontaneous posterior interosseous neuropathy is a relatively rare neuropathy and its etiologic mechanism is not clearly understood yet. The present study was based on a retrospective review of the electrodiagnostic records of 13 patients with spontaneous posterior interosseous neuropathy diagnosed at the EMG laboratory of Seoul National University Hospital from 1978 to 1992. Clinical and electromyographic features, occupational factors, and relationships between dominant hand and involved side were analyzed for the purpose of investigating the etiologic mechanism of spontaneous posterior interosseous neuropathy.

The results of our study indicate that spontaneous posterior interosseous neuropathy is very rare neuropathy (0.34% of peripheral neuropathy) and repeated forearm movement is not so significantly associated with the development of spontaneous posterior interosseous neuropathy. We suggest some etiologic mechanisms of spontaneous posterior interosseous neuropathy as follows: 1) compression by tumor, 2) acute compressive injury by external compression, 3) acute compressive injury by increased internal pressure, 4) entrapment neuropathy by fibrotic arcade fo Frohse.

Keywords :Posterior interosseous neuropathy, Etiologic mechanism, Electrodiagnostic study